Sparge refrigeration technology reachs his to apply

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A large number of application of the difficult treatment material such as the high temperature alloy such as titanium radical, nickel radical and high strenth alloy steel, to cutting treatment brought very great difficulty. Because a large number of heat in metal cutting of the generation when cutting cannot send out in time, make the durability of cutting cutting tool is reduced not only, and the precision that assures workpiece hard and exterior surface roughness, serious when even cannot cutting. Accordingly, reduce heat in metal cutting to have important sense to the treatment of difficult treatment material. To the cutting treatment of average data, how to improve cutting efficiency, prolonging cutting tool life also is the problem that people solves hard all the time. It is especially in treatment of heavy-duty turning, milling, if can make cutting efficiency raises one times, was equivalent to the heavy-duty machine tool with high price increasing one times, that is to say, below the circumstance that does not increase fixed assets investment, make productivity broke up one time. And the extension of cutting tool life, reduced cutting tool cost use up, make manufacturing cost is able to reduce. The cutting tool refrigeration in working process and lubricating is to solve the significant step of afore-mentioned problems to be in working process, the means that lubricates without cooling and lubricant, refrigeration reachs those who machine precision to wait to rise to efficiency of cutting tool durability, cutting have very big effect. In recent years, industrial developed country uses sparge refrigeration technology in metallic cutting process, for cutting treatment offerred the alternative of new cooling technology. Current, outside importing a machine tool to use sparge refrigeration technology except the part, the application on domestic other machine tool is less. The article combines our country national condition, to producing the application in practice this technology undertakes an analysis and put forward to improve measure. The mechanism cutting fluid with one cooling sparge is main in metallic cutting have two effect, it is lubricant action; 2 it is cooling action. Cutting fluid whether the lubricant action with sufficient significant play, its permeate ability to lose by force is a main factor. Groovy pouring the osmosis of type cutting fluid in cutting treatment permeates with the liquid and gas permeates two kinds of means to undertake: Pouring liquid permeates efficiency inferior, lead in effectiveness for a given period of time of high speed cutting lower; As a result of,gas is permeated is pouring the liquid in crackle of the surface that cut bits produces vaporization as the rise of cutting temperature and forward knife face undertakes osmotic. The experiment proves, the osmosis of groovy cutting fluid capability is not strong, can be measured by the liquid of vaporization very few, make lubricant effect is restricted. And the two-phase fluid that sparge refrigeration forms, what can make up for cutting fluid to permeate ability is insufficient. Eject of fluid of gas fluid two-phase arrives cutting zone time, have higher rate, kinetic energy is bigger, because this permeates ability stronger. In addition, size of liquid of the minim in enraging fluid two-phase efflux is very small, encounter the metal with higher temperature extremely easy vaporization, can permeate from face of many knives before facing cutting tool. Although the liquid quantity in efflux is very few, but be compared by the part of vaporization successive and pouring when cutting fluid much, lubricant effect is consequently better. In metallic treatment heat in metal cutting basically originates metallic plasticity is out of shape, the cooling process of cutting area is solid and fluid between conduct heat process. As a result of the appeal between fluid and solid element and fluid viscosity action, there is sluggish of a fluid to shed a layer in solid surface, increased thermal resistance thereby. Sluggish shedding layer is thicker, thermal resistance is greater, and the ply of sluggish shedding layer basically depends on the fluidity of the fluid namely viscosity. The fluid refrigeration effect with the fluid refrigeration bigger than viscosity effect with little viscosity is good. The dynamical viscosity of fluid of steam fluid two-phase can express with next type: F of μ = μ - (μ F - in type of μ G)x  , μ F is the dynamical viscosity of the fluid, μ G is dynamical viscosity of gas, x is quality coefficient, x ＝ Wf/WfWg(Wf is fluid photograph mass flow, wg is) of gas phase mass flow. Apparent, f of μ of < of the μ in type, the viscosity μ that enrages fluid two-phase to mix a fluid namely always is less than single-phase liquid viscosity, i.e. sparge drops in temperature coolingly the effect wants excel single-phase cutting fluid. When fluid of gas fluid two-phase is ejective, bulk expands to do work external abruptly, wasted internal energy, can make temperature reduces 10 ℃ to control. Fluid of the two-phase in sparge refrigeration has higher rate, can sweep scrap in time, take away much quantity of heat, increased to drop in temperature further the effect. Accordingly, sparge refrigeration enrages fluid integratedly actually of two kinds of fluids drop in temperature the effect and advantage. In the working principle sparge of unit of 2 sparge refrigeration cools even if circulating air of pressure of minim liquid interfuse, form the fluid of gas fluid two-phase of mist shape, produce efflux through sparge, eject arrives cutting area, make workpiece and cutting tool get cool adequately and lubricating. When sparge refrigeration unit works, compress air to be enraged via dividing water filter implement filter removes the impurity such as moisture, the one fraction after carrying electromagnetism a powerful person compresses air to enter cooling fluid case inside, will cooling hydraulic pressure gives spray head; The majority compresses air classics pressure regulator valve to move pressure to 0.

32 ～ 0.

The classics after 35MPa compresses air hose to mix to nozzle and cooling fluid, the eject after pulverization arrives cutting area. The key of cooling technology depends on sparge whether cooling fluid sufficient pulverization. Because the pressure of cooling fluid is more than slightly,reduce airy pressure, both mixes inside gas fluid mixing chamber hind, via cooling pipe of type of flexible metal conduit 5 by nozzle head ejective. Conversely, if the pressure of cooling fluid is less than,reduce airy pressure, criterion cooling fluid will be pressed to return cooling fluid case inside. In the sparge refrigeration unit in machine tool of a few entrances, compressing air is from what cooling fluid case enters after pressure regulator valve, because this is ejective,often have when cooling fluid " pant " phenomenon. If will compress air instead,from electromagnetism hind of a powerful person enters cooling fluid case directly, can avoid " pant " phenomenon. To adjust ejective cooling current is measured, control valve of cooling fluid discharge was installed on nozzle. The sparge refrigeration device that place of machine tool of a few entrances uses, its nozzle control valve is taper, the bulk that clearance cooperates through adjusting cone when using will adjust cooling fluid discharge. Because machine the nozzle control valve of this kind of structure to compare difficulty, of lever of a powerful person and cone of body of a powerful person homocentric degree assure not easily, cannot adjust effectively thereby the discharge of cooling fluid. The experiment proves, if change awl a powerful person smooth a powerful person, change cone plane, increase a sealing ring, criterion the discharge of cooling fluid can adjust arbitrarily. Because the choice of 3 cooling fluid becomes mist state from the cooling fluid with ejective nozzle, among them major in season arrives cutting area, one fraction dispersion is in air, cause harm to handlers to avoid environmental pollution to reach, the option of cooling fluid is very important. Oily kind of cooling fluid besides can cause an environment to pollute, the oily mist adsorption in air is in dispersion go up with the dress on handlers body, may endanger its health, because this is unfavorable,use. To improve antirust, anticorrosive performance, cooling fluid of agent of most and commonly used emulsion, water is contained inferior sodium nitrate and the component such as 3 alcohol amine. Because nitrite is a kind of harmful to human body material, its harm sex is bigger after adding amine of on 3 alcohol, because this is unsuited,use as sparge refrigerant. Shenzhen is very rich the 763 cutting fluid of a company production, do not contain according to introducing inferior sodium nitrate and the component such as 3 alcohol amine, very low to the harm sex of human body, use as sparge refrigerant effect is very good. The temperature of area of applied effect cutting with 4 cooling sparge uses sparge refrigeration and dry cutting to machine respectively 40Cr and 45 steel (the cutting parameter that processes 40Cr steel is: Ap ＝ 2mm, f ＝ 0.

48mm/r, v ＝ 167m/min) . The result that cutting area temperature checks makes clear, compare with dry cutting photograph, temperature of area of the cutting when using sparge to cool can reduce 140 ℃ ; If process 45 steel (Ap ＝ 2mm, f ＝ 0.

3mm/r) , 200 ℃ can be reduced when temperature of area of the cutting when using sparge to cool compares dry cutting. Cutting tool life is in establish the rough machining on the car 45 steel cast, use bit name is YT5. When cutting condition is same, the cutting tool life that uses sparge refrigeration is 1 hour of above, and the cutting tool life when using dry cutting is 30 ～ 40 minutes only. Exterior surface roughness is face of the cent in the turbine cylinder of ZG20CrMo in material of mill of the essence on numerical control planer-type milling machine, use bit name is YT535, cutting dosage is V ＝ 150m/min, vf ＝ 40mm/min, ap=0.

02 ～ 0.

04mm. When using dry cutting, the razor blade after machining 1m2 wears away, treatment surface surface roughness is not stable, for Ra2.

3 ～ 3.

4 μ M; When using sparge to cool, machine 1.

The razor blade after 5m2 wears away, exterior surface roughness is stable, amount to Ra0.

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9 μ M, exceed blueprint to design the Ra=1 of the requirement.

6 μ M. In addition, the different machine tool such as milling machine of boring of lathe of lathe of type of Yu Li of applicable of sparge refrigeration technology, center lathe, rotor, shroud lathe, be born, treatment efficiency rises on average 20% , cutting tool life raises one times above, treatment precision also has rise significantly. If be on rotor lathe journal of fine vehicle rotor, car of the one knife when using dry cutting does not come down, cylinder is spent assure not easily, and when using sparge to cool, one knife can the car is over, and cylinder spends contented design requirement. 5 epilogue have good refrigeration and lubricant effect as a result of sparge refrigeration, in cutting sparge of the application in machining a process cools the technology can raise cutting to machine manufacturing efficiency and component to machine quality significantly. To cutting as a result of two-phase efflux Ou Youqing manages action, reduced oxidation skin, fine scrap to wait for pair of cutting tool wear away, can raise the durability of cutting tool; Volume of sparge refrigeration unit is minor, installation operation is convenient; Amount of cooling fluid cost is little, working environment is clean, those who be helpful for protecting handlers is healthy. Sparge refrigeration technology suits to be used at the calorific generous such as grinding of feed of high speed cutting, delay, heavy-cut grinding to process data of alloy steel of the high strength with circumstance and treatment precision high demand, tall hardness particularly. Cooling device uses spray at numerical control machine tool, can implement cooling automation; If apply on general accuracy machine tool, through simplifying structure, replace the filter that divide water to enrage with switch of road of hand take offense implement with electromagnetism a powerful person, cost can be reduced while implementation sparge is cooling. CNC Milling CNC Machining